Table 2. Health benefits of maize wet milling by-products rich in phytochemicals, and their functional food ingredients.

Phytochemical	Health benefit	By-product and (co-product) rich in phytochemicals	Functional food ingredient from the by-products	Reference
Phytosterols: sterols and stanols (e.g. β-sitosterol, stigmasterol, campesterol)	Reduce cholesterol absorption in the intestine, prevent cardiovascular diseases, reduce oxidized low-density lipoprotein levels, reduce colon tumours, prevent osteoarthritic degradation	Maize bran/fibre (fibre oil) Maize germ (germ oil)	Fibre oil (rich in phytosterols) Cold-pressed maize germ oil	(15, 20, 27, 42, 43, 74)
Tocols/tocochromanols (tocopherols and tocotrienols) (α, β, γ, δ)	Protect cells from free radicals, strengthen the immune system by T-lymphocytes, prevent cardiovascular diseases	Maize germ (germ oil) Maize fibre (fibre oil)	Germ oil Rich in γ-tocopherols Fibre oil	(15, 22, 75)
Carotenoids: xanthophylls (lutein, zeaxanthin), β-carotene	Prevent cancer, protect eye health, prevent cardiovascular diseases and strengthen the immune system	Maize gluten meal	Not available	(10, 53, 54)
Policosanols: octacosanol, triacontanol, hexacosanol, dotriacontanol	Reduce blood lipid levels and platelet aggregation	Maize fibre	Not available	(45, 46, 76)
Phospholipids: phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl inositol, phosphatidyl serine	Hypocholesterolaemic, cardioprotective, hepatoprotective, hypolipidaemic and anticarcinogenic. Phosphatidyl choline is beneficial in brain and mental development, by neural transmission and can treat neurological disorders	Maize germ	Phospholipid-based emulsifiers (lecithin) from maize are on the market, patented by Cargill company (e.g. Nestle-NAN)	(14, 15, 75)
Phenolic compounds Simple phenolics (ferulic acid)	Potent antioxidants that prevent inflammation. Ferulic acid bound to soluble corn fibre gum is delivered to the colon to prevent colon inflammatory diseases	Maize fibre	Corn fibre gum, xylooligosaccharides	(27, 77)
Arabinoxylans (copolymers of arabinose and xylose)	Maintain colon health and resist the absorption of cholesterol in the colon. They are strong prebiotics to maintain gut health by increasing Lactobacillus and Bifidobacterium population	Maize fibre	Corn fibre gum and xylooligosaccharides Maize arabinoxylans- functional gluten-free bread	(77–79)
Protein hydrolysates: peptides	Antihypertensive, hepatoprotective, anti-inflammatory, increase alcohol metabolism, antimicrobial	Maize gluten meal	Maize bioactive oligopeptide extracted from non-GMO maize and spray dried powder (smart PEP)	(49, 60–62, 80)